A plurality of virtual local area network (VLAN) registration protocols may be utilized in a network having a first switch coupled to a second switch over a trunk, wherein a first of the VLAN registration protocols may be considered a “defacto” standard for VLAN registration (and pruning) in the network. For VLAN traffic destined for the second switch, the first switch may implement a pruning technique associated with the first VLAN registration protocol. However, if the second switch does not implement the first VLAN registration protocol and instead implements a different, second VLAN registration protocol, the pruning technique implemented by the first switch may incorrectly block (prune) VLAN traffic destined for the second switch. Accordingly, there is a need for a technique to detect whether the second switch implements the first VLAN registration protocol, so that the first switch can determine whether the pruning technique associated with the first VLAN registration protocol should or should not be implemented.